// records have been processed. Applies only to aggregation queries.
func (e *SelectStatement) AggregateResult(output Record) error {
	for i, expr := range e.selectAST.Expression.Expressions {
		v, err := expr.evalNode(nil, e.tableAlias)
		if err != nil {
			return err
		}
		if expr.As != "" {
			output, err = output.Set(expr.As, v)
		} else {
			output, err = output.Set(fmt.Sprintf("_%d", i+1), v)
		}

		if e.Count.StarArg {
			// Handle COUNT(*)
			e.aggregate.runningCount++
			return nil
		}

		val, err = e.Count.ExprArg.evalNode(r, tableAlias)
		if err != nil {
			return err
		}
	} else {
		// Evaluate the (only) argument
		val, err = e.SFunc.ArgsList[0].evalNode(r, tableAlias)
		if err != nil {
			return err
		}
	}

	if val.IsNull() {
		// E.g. the column or field does not exist in the